/*
 * SPI testing utility (using spidev driver)
 *
 * Copyright (c) 2007  MontaVista Software, Inc.
 * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 *
 * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
 */

#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
const int AVR_FRAME_SIZE = 7;

static void pabort (const char *s)
{
        perror (s);
        abort ();
}

static const char *device = "/dev/spidev0.1";
static uint8_t mode;
static uint8_t bits = 8;
static uint32_t speed = 50000; // 50kHz
static uint16_t delay;

static void transfer (int fd)
{
        int ret;
//        uint8_t tx[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//                         0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
//                         0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//                         0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//                         0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//                         0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD,
//                         0xF0, 0x0D, };

        uint8_t tx[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
        uint8_t rx[ARRAY_SIZE(tx)] = { 0, };

        struct spi_ioc_transfer tr = { .tx_buf = (unsigned long) tx,
                                       .rx_buf = (unsigned long) rx,
                                       .len = ARRAY_SIZE(tx),
                                       .delay_usecs = delay,
                                       .speed_hz = speed,
                                       .bits_per_word = bits, };

        ret = ioctl (fd, SPI_IOC_MESSAGE (1), &tr);

        if (ret < 1) {
                pabort ("can't send spi message");
        }

        for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
//                if (!(ret % 6)) {
//                        puts ("");
//                }

                printf ("%.2X ", rx[ret]);
        }

        puts ("");
}

enum { IDLE, RECEIVE };

static void transfer2 (int fd)
{
        int ret;

        uint8_t tx[1] = { 0xFF };
        uint8_t rx[1] = { 0x00 };

        struct spi_ioc_transfer tr = { .tx_buf = (unsigned long) tx,
                                       .rx_buf = (unsigned long) rx,
                                       .len = 1,
                                       .delay_usecs = delay,
                                       .speed_hz = speed,
                                       .bits_per_word = bits, };

        int state = IDLE;
        int cnt = 0;

        while (1) {
                ret = ioctl (fd, SPI_IOC_MESSAGE (1), &tr);

                if (ret < 1) {
                        pabort ("can't send spi message");
                }

                uint8_t byte = rx[0];

//                if (state == IDLE && byte != 0xFF) {
//                        state = RECEIVE;
//                }
//
//                if (state == RECEIVE) {
                        printf ("%.2X ", byte);

//                        if (++cnt >= AVR_FRAME_SIZE) {
//                                state = IDLE;
//                                cnt = 0;
//                                printf ("\n");
//                        }
//                }
        }
}


static void print_usage (const char *prog)
{
        printf ("Usage: %s [-DsbdlHOLC3]\n", prog);
        puts ("  -D --device   device to use (default /dev/spidev1.1)\n"
                        "  -s --speed    max speed (Hz)\n"
                        "  -d --delay    delay (usec)\n"
                        "  -b --bpw      bits per word \n"
                        "  -l --loop     loopback\n"
                        "  -H --cpha     clock phase\n"
                        "  -O --cpol     clock polarity\n"
                        "  -L --lsb      least significant bit first\n"
                        "  -C --cs-high  chip select active high\n"
                        "  -3 --3wire    SI/SO signals shared\n");
        exit (1);
}

static void parse_opts (int argc, char *argv[])
{
        while (1) {
                static const struct option lopts[] =
                                { { "device", 1, 0, 'D' }, { "speed", 1, 0, 's' }, { "delay", 1, 0, 'd' }, { "bpw", 1, 0, 'b' }, { "loop", 0, 0, 'l' }, { "cpha", 0, 0, 'H' }, { "cpol", 0, 0, 'O' }, { "lsb", 0, 0, 'L' }, { "cs-high", 0, 0, 'C' }, { "3wire", 0, 0, '3' }, { "no-cs", 0, 0, 'N' }, { "ready", 0, 0, 'R' }, { NULL, 0, 0, 0 }, };
                int c;

                c = getopt_long (argc, argv, "D:s:d:b:lHOLC3NR", lopts, NULL);

                if (c == -1)
                        break;

                switch (c) {
                case 'D':
                        device = optarg;
                        break;
                case 's':
                        speed = atoi (optarg);
                        break;
                case 'd':
                        delay = atoi (optarg);
                        break;
                case 'b':
                        bits = atoi (optarg);
                        break;
                case 'l':
                        mode |= SPI_LOOP;
                        break;
                case 'H':
                        mode |= SPI_CPHA;
                        break;
                case 'O':
                        mode |= SPI_CPOL;
                        break;
                case 'L':
                        mode |= SPI_LSB_FIRST;
                        break;
                case 'C':
                        mode |= SPI_CS_HIGH;
                        break;
                case '3':
                        mode |= SPI_3WIRE;
                        break;
                case 'N':
                        mode |= SPI_NO_CS;
                        break;
                case 'R':
                        mode |= SPI_READY;
                        break;
                default:
                        print_usage (argv[0]);
                        break;
                }
        }
}

int main (int argc, char *argv[])
{
        int ret = 0;
        int fd;

        parse_opts (argc, argv);

        fd = open (device, O_RDWR);
        if (fd < 0)
                pabort ("can't open device");

        /*
         * spi mode
         */
        ret = ioctl (fd, SPI_IOC_WR_MODE, &mode);
        if (ret == -1)
                pabort ("can't set spi mode");

        ret = ioctl (fd, SPI_IOC_RD_MODE, &mode);
        if (ret == -1)
                pabort ("can't get spi mode");

        /*
         * bits per word
         */
        ret = ioctl (fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
        if (ret == -1)
                pabort ("can't set bits per word");

        ret = ioctl (fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
        if (ret == -1)
                pabort ("can't get bits per word");

        /*
         * max speed hz
         */
        ret = ioctl (fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
        if (ret == -1)
                pabort ("can't set max speed hz");

        ret = ioctl (fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
        if (ret == -1)
                pabort ("can't get max speed hz");

        printf ("spi mode: %d\n", mode);
        printf ("bits per word: %d\n", bits);
        printf ("max speed: %d Hz (%d KHz)\n", speed, speed / 1000);

        transfer2 (fd);

        close (fd);

        return ret;
}
